This invention relates to aquarium filters, and, more particularly, to a combination filter and aerator for use at high flow rates of 50 gal/hr and more.
Aquarium filters are well-known, and typically comprise means for introducing water to be filtered from the aquarium into the filter, means for filtering the water, and means for returning the filtered water into the aquarium. Filters may be mounted inside the aquarium or on the outside.
Exemplary of filters mounted on the outside include U.S. Pat. No. 3,273,717, issued to H. M. Canterbury on Sept. 20, 1966. In that combination filter and aerator, water is drawn by a pump from the aquarium into the filter through a suction tube, circulated through the filter and returned to the aquarium by means of a discharge tube. However, the electric motor driving the pump is included in the same housing as the filter, thereby providing the possibility of electric shock. Further, the flow rate is limited by the size of the electric motor, and the size of the motor is limited by the filter housing in which it is located.
Filters that employ air as the pump means are exemplified by U.S. Pat. No. 2,782,161, issued to H. W. Willinger et al on Feb. 19, 1957. That filter, mounted inside the aquarium, is limited in its pumping capability by the depth of the aquarium. Further, since the discharge tube exits vertically above the filter housing, it is clear that only limited circulation of the aquarium water can occur, thereby reducing the ability of the filter to remove all solid impurities and particulate matter in the aquarium.
There remains a need to provide an aquarium filter capable of handling a high flow rate of at least about 50 gal/hr substantially noiselessly.